In situ gap inspection robot system and method

ABSTRACT

Systems and methods for in situ gap inspection in a machine, such as a generator, an electric motor, or a turbomachine are described. A robotic crawler has multidirectional traction modules, an expandable body, and sensor modules. A control system communicates with the robotic crawler to provide a control signal to navigate an inspection path within an annular gap of the machine. The inspection path includes axial and radial movements to inspect the annular gap using the sensor modules.

BACKGROUND OF THE INVENTION

The disclosure relates to inspection of machinery and, morespecifically, inspection using a robot inserted into an annular gapspace, such as an air gap, in a generator, electric motor, orturbomachine, including turbo-generators.

The disclosure is related to concurrently filed U.S. patent applicationSer. No. 15/652,730, entitled “MODULAR CRAWLER ROBOT FOR IN SITU GAPINSPECTION” filed Jul. 18, 2017, the entire contents of which areincorporated herein by reference. The disclosure is related toconcurrently filed U.S. patent application Ser. No. 15/652,771, entitled“END REGION INSPECTION MODULE AND METHOD FOR IN SITU GAP INSPECTIONROBOT SYSTEM” filed Jul. 18, 2017, the entire contents of which areincorporated herein by reference. The disclosure is related toconcurrently filed U.S. patent application Ser. No. 15/652,859, entitled“OMNIDIRECTIONAL TRACTION MODULE FOR A ROBOT” filed Jul. 18, 2017, theentire contents of which are incorporated herein by reference. Thedisclosure is related to concurrently filed U.S. patent application Ser.No. 15/652,805, entitled “ACTUATED SENSOR MODULE AND METHOD FOR IN SITUGAP INSPECTION ROBOTS” filed Jul. 18, 2017, the entire contents of whichare incorporated herein by reference.

A visual, mechanical, and/or electrical inspection and testing of agenerator, electric motor, or turbomachine should be performed on aperiodic basis. For example, generators may be inspected and testedperiodically in the field for stator wedge tightness, visual surfaceanomalies, electromagnetic core imperfections, etc. Generator/statorinspection and testing procedures may require complete disassembly ofthe stator and removal of the generator rotor from the stator before anyinspections or tests can be performed on the unit. The cost ofdisassembly and removal of the rotor, the time it takes for thisprocess, and the dangers of rotor removal may impact the frequency ofsuch inspections.

In situ inspection of generators has been performed employing poles,trolleys, scopes, and rotor turning techniques. These procedures may notaccomplish the inspection task in a complete, timely, or safe manner.

Use of a robotic crawler capable of insertion through the radial air gapbetween the core iron and the retaining ring permits in situ inspectionof the rotor and the stator core. The crawler may be inserted in acollapsed position into the gap and expanded by spring return pneumaticrams to the width of the air gap. The crawler may be remotely controlledby a technician and provides video cameras and other inspection tools toperform generator rotor and stator inspections within the air gap as thecrawler is driven to selected locations. The crawler may be maneuveredby the technician within the air gap using video for both navigation andvisual inspection.

BRIEF DESCRIPTION OF THE INVENTION

A first aspect of this disclosure provides a system for in situ gapinspection. A robotic crawler has a plurality of multidirectionaltraction modules, an expandable body connected to the multidirectionaltraction modules, and a plurality of sensor modules positioned by theplurality of multidirectional traction modules. A control system is incommunication with the robotic crawler. The control system provides acontrol signal to the robotic crawler to navigate an inspection pathwithin an annular gap of a machine. Navigating the inspection pathincludes axial movement and circumferential movement of the plurality ofmultidirectional traction modules to inspect the annular gap using theplurality of sensor modules.

A second aspect of the disclosure provides a method for in situ gapinspection. A robotic crawler is inserted into an annular gap of amachine. An expandable body of the robotic crawler is expanded such thata plurality of multidirectional traction modules on the robotic crawlerengage opposed surfaces in the annular gap. The robotic crawlertraverses an inspection path within the annular gap using axialmovements and circumferential movements. A plurality of inspection testsare performed along the inspection path using a plurality of sensormodules on the robotic crawler.

A third aspect of the disclosure provides a robot control system for insitu gap inspection. A crawler configuration module provides operatinginstructions for a robotic crawler having a plurality ofmultidirectional traction modules, an expandable body connected to themultidirectional traction modules, and a plurality of sensor modules. Atleast one inspection path definition correlates to an inspection pathwithin an annular gap of a machine. The machine is selected from agenerator, an electric motor, or a turbomachine. An autonomousnavigation module is in communication with the robotic crawler toprovide a control signal for the robotic crawler to traverse theinspection path using axial movements and circumferential movements ofthe plurality of multidirectional traction modules to inspect theannular gap using the plurality of sensor modules.

The illustrative aspects of the present disclosure are arranged to solvethe problems herein described and/or other problems not discussed.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this disclosure will be more readilyunderstood from the following detailed description of the variousaspects of the disclosure taken in conjunction with the accompanyingdrawings that depict various embodiments of the disclosure, in which:

FIG. 1 shows a diagram of an example system for in situ gap inspectionaccording to various embodiments of the disclosure.

FIG. 2 shows a side section view of gap insertion of a robotic crawlerinto a machine.

FIG. 3 shows a side section view of an expanded robotic crawler in theannular gap of a machine.

FIG. 4 shows a perspective cutaway view of an expanded robotic crawlerin the annular gap of a machine.

FIGS. 5A and 5B shows example inspection paths of a robotic crawler inthe annular gap of a machine according to various embodiments of thedisclosure.

FIG. 6 shows a perspective view of a robotic crawler in its expandedstate according to various embodiments of the disclosure.

FIG. 7 shows a top view of the robotic crawler of FIG. 6 in itscollapsed state.

FIG. 8 shows an end view of the robotic crawler of FIG. 6 in itscollapsed state.

FIG. 9 shows a perspective view of a multidirectional traction moduleaccording to various embodiments of the disclosure.

FIG. 10 shows a side section view of a traction assembly in its flatmode according to various embodiments of the disclosure.

FIG. 11 shows a side section view of the traction assembly of FIG. 10 inits clearance mode.

FIG. 12 shows a side section view of a position lock for the tractionassembly of FIGS. 10-11.

FIG. 13 shows a side cross-sectional view of an expansion link accordingto various embodiments of the disclosure.

FIG. 14 shows a side view of a robotic crawler with example visualinspection and navigation fields of view.

FIG. 15 shows top perspective view of an example navigation sensormodule.

FIG. 16 shows a bottom perspective view of an example visual inspectionsensor module.

FIG. 17 shows a top perspective view of the example visual inspectionsensor module of FIG. 16.

FIG. 18 shows a top perspective view of an example wedge tightness testsensor module.

FIG. 19 shows a top perspective view of an example electromagneticimperfection detection test sensor module.

FIG. 20 shows a top perspective view of an example end region visualinspection sensor module.

FIG. 21 shows a close-up top perspective of the connector assembly ofthe end region visual inspection sensor module of FIG. 20.

FIG. 22 shows a side cutaway view of an example deployment of an endregion visual inspection sensor module in the annular gap of a machine.

FIG. 23 shows a top perspective view of an example series of stackedmodules.

It is noted that the drawings of the disclosure are not necessarily toscale. The drawings are intended to depict only typical aspects of thedisclosure, and therefore should not be considered as limiting the scopeof the disclosure. In the drawings, like numbering represents likeelements between the drawings.

DETAILED DESCRIPTION OF THE INVENTION

In the following description, reference is made to the accompanyingdrawings that form a part thereof, and in which is shown by way ofillustration specific exemplary embodiments in which the presentteachings may be practiced. These embodiments are described insufficient detail to enable those skilled in the art to practice thepresent teachings and it is to be understood that other embodiments maybe used and that changes may be made without departing from the scope ofthe present teachings. The following description is, therefore, merelyillustrative.

Where an element or layer is referred to as being “on,” “engaged to,”“disengaged from,” “connected to” or “coupled to” another element orlayer, it may be directly on, engaged, connected or coupled to the otherelement or layer, or intervening elements or layers may be present. Incontrast, when an element is referred to as being “directly on,”“directly engaged to,” “directly connected to” or “directly coupled to”another element or layer, there may be no intervening elements or layerspresent. Other words used to describe the relationship between elementsshould be interpreted in a like fashion (e.g., “between” versus“directly between,” “adjacent” versus “directly adjacent,” etc.). Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

Referring to FIG. 1, an example system 100 for in situ gap inspection isshown. System 100 may include a robotic crawler 110, a tether reel 130,and a control system 150. Robotic crawler 110 may be configured to beinserted through an entrance gap into an annular gap in a machine toconduct autonomous or semi-autonomous inspection of the machine. Forexample, robotic crawler 110 may be a collapsible robot that can operatein a collapsed or expanded state and may be inserted through a narrowentrance gap in its collapsed state and expand to a wider gap width suchthat it engages the opposed surfaces of the annular gap. Robotic crawler110 is shown in its expanded state in FIG. 1. Once in the annular gap,robotic crawler 110 may navigate the annular gap and use one or moresensor modules to conduct various inspection tests during its movementsor at various desired crawler positions in the annular gap. Roboticcrawler 110 may be configured for multidirectional movement, includingforward and reverse movement in the axial direction and bi-directionallateral movement in the circumferential direction. In some embodiments,robotic crawler 110 may be configured for omnidirectional movement thatincludes bi-directional movement in any orientation between the axialand circumferential directions, in addition to the axial andcircumferential directions. For example, robotic crawler 110 may beconfigured to move in any direction in a 360 degree arc and freelychange its direction of travel to any orientation in the 360 degree arc,including a plurality of directions between and angled from the axialand circumferential directions. In some embodiments, robotic crawler 110may include a tether 132 connected to robotic crawler 110 and extendingout of the machine during operation. For example, tether 132 may be acable connected to robotic crawler 110 to enable retrieval of roboticcrawler 110 in the event that robotic crawler 110 cannot navigate out ofthe annular gap under its own power. In some embodiments, tether 132 mayprovide a physical connection from robotic crawler 110 for a wiredcommunication channel and/or a remote power source and/or pneumatic orhydraulic lines to support test systems or robotic operation. Tetherreel 130 may be automated to adjust the tension and/or slack on tether132 during operation of robotic crawler 110 within the annular gap,enabling robotic crawler 110 to navigate various navigation paths andperform inspection routines without a user manually managing theposition of the tether. Control system 150 may be in communication withrobotic crawler 110 to provide control signals to robotic crawler 110and receive sensor, navigation, and/or other operational data fromrobotic crawler 110. In some embodiments, control system 150 may beelectrically connected to tether 132 directly or through tether reel 130and the electrical connection may include one or both of a power channeland a communication channel. Control system 150 may provide a userinterface for a user to monitor, evaluate, supplement, and/or controlrobotic crawler 110 during an inspection deployment within the annulargap of the machine.

In some embodiments, robotic crawler 110 is a modular robot that may bereconfigured for different inspection tasks and enabling efficientmaintenance, replacement, and/or upgrade of individual modules. Roboticcrawler 110 may include a body frame, such as an expandable body 112,for receiving, positioning, and connecting various modules relative toone another. In some embodiments, expandable body 112 accommodates aplurality of traction modules 114, 116, 118. For example, roboticcrawler 110 may include three traction modules 114, 116, 118, a forwardtraction module 114, a middle traction module 116, and a rear tractionmodule 118, where forward traction module 114 and rear traction module118 are configured to engage a first surface in the annular gap and themiddle traction module 116 is configured to engage an opposed secondsurface in the annular gap. Traction modules 114, 116, 118 may bemultidirectional traction module capable of moving robotic crawler 110in multiple directions, including both axial and circumferentialmovement within the annular gap. Robotic crawler 110 may further includea plurality of sensor modules 120, 122, such as visual sensors fornavigation and/or visual inspection. For example, sensor modules 120,122 may be attached via sensor interfaces on the forward and rear sidesof middle traction module 116 and may provide both forward and rearfacing navigation cameras, as well as one or more upward facing camerasfor inspecting the adjacent surface of the annular gap. Robotic crawler110 may also include one or more tether connectors 124, 126 fordetachably receiving tether 132, generally with a compatible endconnector 134 and fasteners 136, 138.

In some embodiments, tether reel 130 is an automated tether reel thatmay receive, release, and spool tether 132 to adjust tension as neededduring operation of robotic crawler 110. For example, tether reel 130may include a servo motor 142 and tension management logic 144. Forexample, servo motor 142 operating in a torque/current control mode maydetect changes in tension on tether 132 as it enters tether reel 130 andtension management logic 144 may provide an algorithm for maintaining anacceptable tension range using servo motor 142 to reel in or reel outtether 132 under closed loop control. In some embodiments, tether 132may have a fixed connection 146 to tether reel 130 and a separate wire148 may connect to control system 150. For example, wire 148 may providecommunication and/or power channels without providing the mechanicalcharacteristics desired for tethering robotic crawler 110. In someembodiments, tether reel 130 may provide an interface for receivingcontrol signals for tether reel 130 from control system 150. Forexample, control system 150 may be able to adjust tension control ormotor parameters and/or manually override operation of tether reel 130.In some embodiments, robotic crawler 110 may operate without a tether,carry its own power (e.g., batteries), and/or use wireless communicationwith control system 150.

In some embodiments, control system 150 may include a computing system152. Computing system 152 may provide a plurality of programmaticcontrols and user interface for operating robotic crawler 110. In someembodiments, computing system 152 is a general purpose computingdevices, such as a personal computer, work station, mobile device, or anembedded system in an industrial control system (using general purposecomputing components and operating systems). In some embodiments,computing system 152 may be a specialized data processing system for thetask of controlling operation of system 100. Computing system 152 mayinclude at least one memory 154, processor 156, and input/output (I/O)interface 158 interconnected by a bus. Further, computing system 152 mayinclude communication with external I/O device/resources and/or storagesystems, including connected system, such as robotic crawler 110, tetherreel 130, and network resources. In general, processor 156 executescomputer program code, such as inspection control module 160, that isstored in memory 154 and/or a storage system. While executing computerprogram code, processor 156 can read and/or write data to/from memory154, storage systems, and I/O devices (through I/O interface 158). Thebus provides a communication link between each of the components withincomputing system 152. I/O devices may comprise any device that enables auser to interact with computing system 152 (e.g., keyboard, pointingdevice, display, etc.). Computing system 152 is only representative ofvarious possible combinations of hardware and software. For example, theprocessor may comprise a single processing unit, or be distributedacross one or more processing units in one or more locations, e.g., on aclient and server. Similarly, memory and/or storage systems may resideat one or more physical locations. Memory and/or storage systems cancomprise any combination of various types of non-transitory computerreadable storage medium including magnetic media, optical media, randomaccess memory (RAM), read only memory (ROM), etc. In some embodiments,computing system 152 is a laptop computer in communication with roboticcrawler 110 via a wired (serial, USB, Ethernet, etc.) or wireless(802.11, Bluetooth, etc.) connection and running application softwarefor system 100. In some embodiments, some or all of the functions ofcomputing system 152 may be on board robotic crawler 110 using anintegrated computing system, such as an on board control module, with orwithout wireless communication to one or more user interfaces and/orremote data storage.

In some embodiments, computing system 152 may include one or moreapplication programs, data sources, and/or functional modules forcontrolling robotic crawler 110. For example, computing system 152 mayinclude inspection control module 160 that operates in conjunction withdata sources 162, 164, 166, 168 to provide control signals to andreceive data from robotic crawler 110. Inspection control module 160 mayprovide a visual display module 170. For example, visual data collectedby cameras on robotic crawler 110 may be displayed by visual displaymodule 170, such as a graphical user interface for one or more videofeeds. In some embodiments, visual data from robotic crawler 110 may bestored in visual data source 164 for use by visual display module 170and/or selective, temporary, and/or archival storage of visual data forlater use, including use by other users or systems. Data display module172 may provide display, including visual display, of other test data,including processed visual data and resulting calculations or analysis.For example, data display module 172 may include a graphical userinterface for test results from one or more test protocols using sensorand navigation data from robotic crawler 110. In some embodiments, testdata from robotic crawler 110 may be stored in test data source 166 foruse by data display module 172 and/or selective, temporary, and/orarchival storage of test data for later use, including use by otherusers or systems. Data display module 172 may include a real-timedisplay of test data as it is collected by robotic crawler 110 and/orone or more functions for viewing, aggregating, analyzing, visualizing,selecting, and/or reporting test data from test data source 166.Autonomous navigation module 174 may provide a protocol or series ofcommands for navigation of robotic crawler 110 within the annular gap ofthe machine. In some embodiments, autonomous navigation module 174enables a user to select an inspection path from a plurality ofinspection paths stored in inspection path data source 162. For example,inspection paths may be defined as physical paths robotic crawler 110should follow within the annular gap to complete one or more inspectiontasks in one or more locations within the annular gap. Inspection pathsmay be based on a physical schematic or parameters of one or moremachines defining axial and circumferential distances. Inspection pathsmay also include parameters and locations related to specific featuresof interest for either navigation (e.g., surface features to be avoided)or for testing (e.g., locations or corresponding crawler positions forconducting specific tests). In some embodiments, inspection paths may bestored and defined in terms of a sequence of crawler commands.Autonomous navigation module 174 may enable autonomous navigation byrobotic crawler 110 receiving and executing a sequence of crawlercommands without user intervention once the autonomous operation isinitiated. In some embodiments, autonomous navigation module 174 mayhave completely autonomous inspection routines that require no userintervention once initiated or may include a plurality of inspectionsubroutines, such as specific movement patterns, position changes, ortest protocols, that are initiated in a desired sequence by a user,potentially based on navigational, visual, or test data feedback. Manualnavigation module 176 may provide a user with the ability to pilot orotherwise control robotic crawler 110. In some embodiments, manualnavigation module 176 may be provided for establishing an initialposition for initiating automated control and/or allow a user tooverride automated control in response to problems, exceptions, orspecific test protocols (such as an initial test result that requiresfurther data gathering). In some embodiments, control system 150 mayinclude one or more user I/O interfaces for manually controlling roboticcrawler 110, such as joysticks and other tactile controls, fornavigation, deploying sensors, and conducting various test protocols.Inspection module 178 may provide a plurality of routines for variousinspection protocols using one or more sensor modules. In someembodiments, one or more sensor protocols are stored in sensor protocoldata source 168 for use by inspection module 178. For example, a visualinspection protocol may include activating and capturing visual datafrom one or more sensor modules on robotic crawler 110 along a definednavigation path to enable mapping of captured visual data to locationinformation with the machine. In some embodiments, a plurality ofcameras with varying facings and/or positionable cameras may be presentin one or more sensor modules 120, 122 and a visual inspection modulemay include selective activation and positioning of robotic crawler 110and its various cameras. An inspection protocol executed by inspectionmodule 178 may include a combination of navigational elements(navigation path, autonomous positioning, and/or manual positioning) andsensor protocols (position requirements, deployment, activation,timing/sampling, parameters, etc.). In some embodiments, inspectionmodule 178 may define the storage of visual data and test data in visualdata source 164 and test data source 166 and/or the display of visualdata by visual display module 170 and test data by data display module172. Crawler configuration module 180 may provide data regarding theconfiguration of modules and related capabilities and protocols for anygiven configuration of robotic crawler 110. In some embodiments, crawlerconfiguration module 180 may map crawler configurations to machinespecifications and sensor protocols to assist a user in matchinginspection protocols with the resources available for a given testdeployment. For example, a given configuration of sensor modules maydefine the test capabilities of robotic crawler 110 and recommendspecific inspection protocols to utilize those sensor modules. In someembodiments, crawler configuration module 180 may include a library ofsensor modules and related capabilities and support user reconfigurationof robotic crawler 110 for a desired inspection protocol. Crawlerconfiguration module 182 may also define the set of crawler commands 184that may be used to control robotic crawler 110. Crawler coordinationmodule 182 may enable inspection control module 160 to control more thanone robotic crawler 110 simultaneously. In some embodiments, crawlercoordination module 182 may maintain a plurality of communicationchannels for control signals and data signals with a plurality ofrobotic crawlers. For example, crawler coordination module 182 maymanage a plurality of instances of visual display module 170, datadisplay module 172, autonomous navigation module 174, manual navigationmodule 176, inspection module 178, and crawler configuration module 180for parallel management of the plurality of robotic crawlers. In someembodiments, crawler coordination module 182 may include interferenceprotection for tracking the current crawler positions, navigation paths,and timing of various movements and sensor protocols to preventcollisions or other interference within the annular gap.

In some embodiments, visual display module 170, data display module 172,autonomous navigation module 174, manual navigation module 176, andinspection module 178 may include issuing one or more crawler commands184 to robotic crawler 110 to complete some aspect of their function.Crawler commands 184 may then be translated into messages or controlsignals from control system 150 to robotic crawler 110. In someembodiments, crawler configuration module 180 may define the set ofcrawler commands available to the other modules based on theconfiguration of robotic crawler 110. An example set of crawler commands184 are provided, but will be understood to be neither exclusive norexhaustive of the possible crawler commands that could be used tocontrol robotic crawler 110 and various configurations of tractionmodules, sensor modules, and body frame mechanics possible. Roboticcrawler 110 may receive expand/contract commands 186 to expand orcontract expandable body 112 between a collapsed state and one or moreexpanded states, such as a control signal to one or more motors thatdrive the body position. In some embodiments, expand or contract may bebased on feedback from sensors within robotic crawler 110 when thetraction modules are in a planar position (for collapsed state) or havecontacted opposed surfaces in the annular gap (for expanded state). Inother embodiments, expand or contract may be based on time (e.g.,activate motor for x seconds of expansion or contraction) or distance(e.g., set crawler width to y inches). Robotic crawler 110 may receivemove commands 188 to drive its traction modules forward or backwards(based on the present alignment of the traction modules in the case ofmultidirectional traction modules). Robotic crawler 110 may receivechange direction commands 190 to reorient its traction modules anddirection of travel. For example, change direction commands 190 mayallow multidirectional traction modules to rotate 90 degrees and changefrom axial orientation and directions of travel to circumferentialorientation and directions of travel. In some embodiments, changedirection commands 190 may include orientation changes of greater orless than 90 degrees and include a feedback signal for confirmingorientation or traction modules and communicating orientation back tocontrol system 150. Robotic crawler 110 may receive traction modecommands 192 to drive changes in the configuration of the tractionmodules for different traction modes. For example, traction modules mayinclude a flat mode for robot insertion and/or low profile and smoothsurface travel and a clearance mode for providing clearance between thebody of robotic crawler 110 and the surfaces it is moving along and/ortraversing obstacles or uneven surfaces. Traction mode commands 192 mayinclude control signals to change from flat mode to clearance mode orfrom clearance mode to flat mode. Robotic crawler 110 may receiveposition sensor commands 194 for sensor modules that include deploymentand/or positioning features. For example, some sensor modules mayinclude electromechanical features for extending, raising, lowering,rotating, or otherwise positioning one or more elements of the sensormodule before, during, or after data collection. Position sensorcommands 194 may include a control signal to activate a motor forextending or otherwise repositioning a sensor from robotic crawler 110to position it for data collection or for moving a sensor (such as byrotation) independent of changing crawler position during datacollection. Robotic crawler 110 may receive acquire data commands 196for initiating data collection through a sensor module using whatevermodality is present in that sensor module. Acquire data commands 196 mayprovide a start or stop signal for a continuous data collection mode,such as a video feed from the camera(s) of a visual sensor, or aspecific test sequence for a more discrete sensor test, such as amechanical wedge tightness test. It will be understood that some roboticcrawlers and control systems may be able to communicate and managemultiple commands in parallel, as overlapping sequences, or as serialcommand series. Crawler coordination module 182 may enable controlsystem 150 to issue commands to and acquire data from multiple roboticcrawlers in parallel.

Referring to FIG. 2, an in situ gap inspection system 200 is shown witha robotic crawler 210, such as robotic crawler 110 in FIG. 1, beinginserted into a machine 202. Machine 202 may be any machine with anannular gap 220 accessible through an entrance gap 222 and, morespecifically, a variety of machine configurations of generators,electric motors, or turbomachines. For example, a generator may allowinsertion through the circumferential air gap between the core iron andthe retaining ring permits in situ inspection of the rotor and thestator core. Annular gap 220 may be defined between a cylindricalcentral member 226 and a surrounding cylindrical member 224 withgenerally complementary curvature. In some embodiments, annular gap 220may be an air gap generally defined by: the inner diameter of the statorminus the outer diameter of the rotor divided by two. Annular gap 220has an axial length from a first end to a second end of cylindricalcentral member 226 and a circumference measured in the direction of thecircumference of cylindrical central member 226. Annular gap 220 has anannular gap width 228 measured from outer surface 236 of cylindricalcentral member 226 to the nearest opposite surface (inner surface 234)of surrounding cylindrical member 224. In some embodiments, entrance gap222 may be an air gap at an end of the central cylindrical member 226and have the same entrance width as annular gap width 228. In otherembodiments, entrance gap 222 may include additional features, such as aretaining member 230, that further constrain entrance gap 222 and definean entrance gap width 232 is that is less than annular gap width 228. Insome embodiments, additional features or obstacles may reduce annulargap width 228, such entrance baffles used to direct cooling air flow.

In FIG. 2, robotic crawler 210 is in a collapsed state, where itstraction modules are aligned in a single plane. Robotic crawler 210 isshown outside entrance gap 222 before insertion and inside annular gap220 after insertion. Robotic crawler 210 may define a collapsed crawlerwidth 212. Collapsed crawler width 212 may be less than both entrancegap width 232 and annular gap width 228. In its collapsed state, roboticcrawler 210 engages only outer surface 236 of central cylindrical member226 inside annular gap 220.

FIGS. 3-4 show two views of robotic crawler 210 in an expanded statewithin annular gap 220. When robotic crawler 210 is in its expandedstate, it may engage opposed surfaces 234, 236. In an expanded state,robotic crawler 210 may define an expanded crawler width 214. Expandedcrawler width 214 may be larger than collapsed crawler width 212 andentrance gap width 232, and equal to annular gap width 228 such thatsurface contact may be maintained with opposed surfaces 234, 236. Insome embodiments, robotic crawler 210 comprises a plurality of tractionmodules 240, 242, 244 mounted in an expandable body 246. Tractionmodules 240, 244 may engage only outer surface 236 of centralcylindrical member 226 and traction module 242 may engage only innersurface 234 of surrounding cylindrical member 236. In some embodiments,the configuration of traction modules 240, 242, 244 may be reversed andtraction modules 240, 244 may engage only inner surface 234 ofsurrounding cylindrical member 236 and traction module 242 may engageonly outer surface 236 of central cylindrical member 226. Tractionmodules 240, 242, 244 may include rollers, including wheels, balls, ortracks, to move robotic crawler 210 through annular gap 220 based onmoving surface contact with opposed surfaces 234, 236. Traction modules240, 242, 244 may move robotic crawler 210 on a desired navigation paththrough annular gap 220.

Referring to FIGS. 5A and 5B, another embodiment of a robotic crawler510 is shown in an annular gap 520 with lines 530, 532 showing examplenavigation paths for inspecting annular gap 520. Robotic crawler 510 isshown in an expanded state in a starting crawler position just insideentrance gap 522 adjacent an entrance end portion 524 of the machine502. Following line 530, robotic crawler 510 moves in a forward axialdirection along a gap length 526 of annular gap 520 from the entranceend portion 524 to the closed end portion 528. In some embodiments,robotic crawler 510 may reach a step or other obstacle representing theend of the navigable gap length 526 of annular gap 520. For example,closed end portion 528 may include a step created by a retaining ring orother feature and may include another air gap into an enclosed endregion of the machine. Robotic crawler 510 may include multidirectionaltraction modules that enable it to change its travel direction from theaxial direction to the circumferential direction. Line 530 shows anumber of circumferential steps along the circumference of annular gap520. The length of the circumferential step may depend on a variety offactors related to sensor range/area (or field of view for visualsensors), test locations, desired test coverage or sampling, and/orspecific machine features to be included in the navigation path tosupport desired test protocols using the sensor modules on roboticcrawler 510. After a new circumferential position is achieved, line 530shows a return path in the reverse axial direction along gap length 526.Robotic crawler 510 may reorient its movement direction back to an axialorientation and move in the opposite direction down the length ofannular gap 520. In some embodiments, robotic crawler 510 may reach astep or other obstacle associated with entrance gap 522 and representingthe end of the navigable gap length 526 of annular gap 520. Roboticcrawler 510 may again reorient its travel direction for circumferentialmovement and make another circumferential step. Robotic crawler 510 maycontinue stepping through these axial passes at various circumferentialpositions along the circumference for the area of annular gap 520 to beinspected with the selected sensor modules and inspection protocol. Insome embodiments, robotic crawler 510 may traverse gap length 236 incircumferential positions providing overlapping coverage for visualinspection around the entire circumference of annular gap 520 to providea complete visual inspection of the surfaces of annular gap 520.Following line 532 shows an alternate inspection path and is provided todemonstrate that a plurality of inspection paths may be enabled bymultidirectional and omnidirectional movement. Line 532 takes roboticcrawler 510 along an inspection path that includes axial travel,circumferential travel, and travel along intermediate orientationsbetween the axial and circumferential directions. More complex and lessrepetitious inspection paths may be used for inspection of specificareas or features, as well as to navigate around known obstacles.

Referring to FIGS. 6-8, an additional embodiment of a robotic crawler600 is shown in several views and including an expanded state in FIG. 6and a collapsed state in FIGS. 7-8. In some embodiments, robotic crawler600 is a modular robot with an expandable body 610 including pluralityof frames 612, 614, 616 for accommodating removable modules. Removablemodules may include traction modules 660, 662, 664 that provide rollers,such as wheels, tracks, or balls, or another form of locomotion formoving robotic crawler 600 along the surfaces within a gap. Roboticcrawler 600 may also accommodate a plurality of sensor modules, such asnavigation sensors, visual inspection sensors, structural test sensors,or electrical test sensors, using sensor interfaces that providemechanical and/or electrical/communication/control between roboticcrawler 600 and the sensor modules. For example, one or more moduleframes may include sensor interfaces and/or the traction modules orother sensor modules may include sensor interfaces for chaining multiplemodules from a single frame. The plurality of sensor interfaces may beprovided at several positions on robotic crawler 600 to providedifferent operating positions for various sensors. For example, each oftraction modules 660, 662, 664 may include one or more sensor interfacesand related sensor positions. In some embodiments, there may be multipleconfigurations of sensor interfaces. For example, sensor interfaces forattachment to traction modules 660, 662, 664 may be different thansensor interfaces between serial sensor interfaces. Other modules mayalso be provided for other functions, such as a tether connector module602.

In some embodiments, expandable body 610 includes generally rectangularbase frame and includes lateral members 618, 620 on the long sides ofthe rectangle, connected to front frame 612 and rear frame 616 providingthe short sides of the rectangle. Lateral members 618, 620 may includeframe attachments 622, 624, 626, 628 proximate their respective distalends. Frame attachments 622, 624 may connect to front frame 612 andframe attachments 626, 628 may connect to rear frame 616. In someembodiments, middle frame 614 may be configured to be displaced from theplane of front frame 612 and rear frame 616 to expand the width ofexpandable body 610 in its expanded state. Middle frame 614 may beattached to extension link members 630, 632, which are connected to therectangular base frame. For example, extension link members 630, 632 mayinclude pivoting attachments 634, 636, 638, 640 with front frame 612 andrear frame 616 or, alternately, with lateral members 618, 620 proximatetheir distal ends. Extension link members 630, 632 may be articulatedlink members with first links 642, 644 and second links 646, 648 havingpivoting attachments 650, 652 to middle frame 614. Pivoting attachments650, 652 may act as an articulated joint in extension link members 630,632 and move middle frame 614 perpendicular to the plane of therectangular base frame. Expandable body 610 may include a motor or otheractuator for moving middle frame 614. For example, lateral members 618,620 may include linear actuators 654, 656 for moving front frame 612relative to rear frame 616, changing the lengths of lateral members 618,620 and the distance between front frame 612 and rear frame 616. Whenlateral members 618, 620 are in their fully extended positions, frontframe 612, middle frame 614, and rear frame 616 may be in the same planeand expandable body 610 is in its narrowest or collapsed state. Aslateral members 618, 620 are shortened by linear actuators 654, 656 andrear frame 616 moves toward front frame 612, extension link members 630,632 articulate at pivoting attachments 650, 652 and first links 642,644, second links 646, 648, and lateral members 618, 620 form anisosceles triangle with middle frame 614 moving in a directionperpendicular to the direction of movement between front frame 612 andrear frame 616. Other configurations of expandable bodies are possible,such as one or more frames being mounted on lever arms, scissor jacks,telescoping members, or other displacement mechanisms. In someembodiments, expandable body 610 may incorporate shock absorbers betweenfront frame 612 and rear frame 616 and middle frame 614 to assist innavigating uneven gap spaces. For example, extension link members 630,632 may incorporate telescoping links with an internal spring to assistwith traction on opposed gap surfaces and compensate for some obstaclesand/or changes in gap spacing. In some embodiments, lateral members 618,620 may include emergency releases 627, 629 to disengage lateral members618, 620 manually in the event of power loss or other failure thatprevents control of linear actuators 654, 656. For example, frameattachments 626, 628 may incorporate mechanical fasteners that attachlateral members 618, 620 to frame attachments 626, 628 and thesemechanical fasteners may act as emergency releases 627, 629 by enablinga user to release the mechanical fasteners and thereby disengage lateralmembers 618, 620 to cause expandable body 610 to collapse into itscollapsed state. In some embodiments, emergency releases 627, 629 may bescrews, bolts, or pins through frame attachments 626, 628 and intolateral members 618, 620 that may be removed to collapse expandable body610. In some embodiments, expandable body 610 has a lateral shape thatis an arc based on the configuration of frames 612, 614, 616 and lateralmembers 618, 620, most visible in FIG. 8. The arc of expandable body 610may be configured to complement the curvature of an annular gap in whichrobotic crawler 600 is intended to operate. For example, the arc orcurvature may be similar to the arc of the outer surface of the centralcylindrical member or the inner surface of the surrounding cylindricalmember that define the annular gap.

In some embodiments, each of frames 612, 614, 616 are configured toreceive, position, and retain traction modules 660, 662, 664. Forexample, traction modules 660, 662, 664 may each be multidirectionaltraction modules with fixed outer frames 666, 668, 670 to removablyattach to frames 612, 614, 616. Traction modules 660, 662, 664 mayinclude rotating inner frames 672, 674, 676 that enable robotic crawler600 to change the orientation of rollers 678, 680, 682 and direction ofmovement. Each of traction modules 660, 662, 664 may also include one ormore interfaces 684, 686, 688, 690 that may be used to attach sensormodules or other functional modules, directly or in series. For example,traction module 660 may include interface 684 and is shown with a visualsensor module 692. Traction module 662 may include interfaces 686, 688and visual sensor modules 694, 696. Traction module 664 may includeinterface 697, visual sensor module 698, and tether connector module602.

FIG. 9 shows an example multidirectional traction module 800 accordingto various embodiments. Traction module 800 may be configured for use ina robotic crawler, such as robotic crawlers 110, 210, 510, 600. Tractionmodule 800 enables the direction and orientation of travel of a roboticcrawler to be changed without changing the orientation of the roboticcrawler itself. Traction module 800 may include a fixed outer frame 810with one or more attachment features 812, 814 configured for attachmentto a robotic crawler, such as insertion into a body frame. In someembodiments, traction module 800 may also include an electricalinterconnect 816 for power and/or control signals from the roboticcrawler to traction module 800. Traction module 800 may include arotating frame 820 seated within fixed outer frame 810 and capable ofrotational movement relative to fixed outer frame 810. For example,rotating frame 820 or fixed outer frame 810 may include an actuator 822,such as a motor and worm gear for moving rotating frame 820. In someembodiments, rotating frame 820 may rotate 90 degrees to change theorientation and direction of travel. In some embodiments, rotating frame820 may traverse or be stopped in various positions or orientationsalong at least a 90 degree arc and/or up to a 360 degree arc. In someembodiments, the worm gear or other drive mechanism incorporates anencoder to measure the angular position or orientation of rotating frame820. For example, reference arcs 824, 826 may provide visual referencethrough reflective and non-reflective coatings to allow and opticalsensor (not shown) to ascertain the orientation of traction module 800.Rotating frame 820 may provide a first position corresponding to forwardand/or reverse (which may generally correspond to the axial directionwithin an annular gap). In some embodiments, roller assembly 830 isdisposed within rotating frame 820 and includes a configuration ofrollers 832, 834 for providing rotating traction to move the roboticcrawler in a direction of rotation. Roller assembly 830 may also includea motor or other actuator for rotating rollers 832, 834. In someembodiments, roller assembly 830 may be driven in a forward or reversedirection in addition to changes in orientation from rotation ofrotating frame 820. In some embodiments, rollers 832, 834 may engage androtate belts 836, 838 to provide traction for traction module 800. Forexample, belts 836, 838 may substantially cover the length of rollers832, 834 to provide a large contact area with adjacent machine surfaces.In some embodiments, belts 836, 838 may include surface features ortreatments to improve traction, such as a textured surface for providinggrip on oily surfaces. In some embodiments, roller assembly 830 mayinclude a roller configuration actuator 870 to support multiple tractionconfigurations and mechanisms for changing between configurations andlocking the selected configuration in place. For example, rollerassembly 830 may be capable of switching between a flat mode to providea lower profile and an obstacle or clearance mode with angled belt pathsfor increasing the clearance between the robotic crawler and thesurfaces it is traveling on. Roller configuration actuator 870 mayactuate the change between the two modes and provide a locking mechanismfor holding each configuration. In some embodiments, rollerconfiguration actuator 870 may incorporate emergency releases 890, 892that may be actuated to return roller assembly 830 to the flat mode inthe event of a power failure or other loss of control of rollerconfiguration actuator 870.

FIGS. 10-12 show roller assembly 830 in flat mode (FIG. 10) andclearance mode (FIG. 11) and roller configuration actuator 870 (FIG. 12)for maintaining the two modes. Roller assembly 830 may have rollers 832,834, 840, 842 in paired axle assemblies 844, 846. Axle assemblies 844,846 may be rotatable around central pivot attachments 848, 850 to adjustbetween flat mode and clearance mode. In flat mode, each axis ofrotation of rollers 832, 834, 840, 842 may be aligned in a single plane852. In clearance mode, axle assemblies 844, 846 rotate rollers 832,834, 840, 842 out of the shared plane and define at least two distinctplanes 854, 856, 858, 860 of operation. For example, plane 854 alignswith the axis of rotation of rollers 832, 834 which support a parallelreturn path for belts 836, 838. Plane 856 aligns with axis of rotationof rollers 840, 842, which support a primary traction path for belts836, 838. Plane 854 is distinct from plane 856. Plane 858 aligns withaxis of rotation of rollers 832, 840 (on axle assembly 844) whichsupports a first climbing traction surface or return path (depending onthe direction of travel). Plane 860 aligns with axis of rotation ofrollers 834, 842 (on axle assembly 846) which supports a second climbingtraction surface or return path (depending on the direction of travel).Once rollers 832, 834, 840, 842 are rotated out of common plane 852, areaction force between the adjacent machine surface and primary tractionsurface may encourage reverse rotation to return to flat mode and alocking mechanism 871 may be included within roller configurationactuator 870 to counteract this tendency. In some embodiments, lockingmechanism 871 may include ratchet ends 872, 874 on pivot attachments848, 850 with claw members 876, 878 to engage ratchet ends 872, 874 andhold them in place in clearance mode under tensioning force from spring880. A powered release mechanism 882 may be provided to controllablysupply an opposing force to the tensioning force from spring 880. Forexample, a shape memory alloy wire 884 between two lever arms 886, 888may contract when heated to release ratchet ends 872, 874 and allowroller assembly 830 to return to flat mode. An electric solenoid orother actuator may provide a similar powered release mechanism 882.Locking mechanism 871 may include manual emergency releases 890, 892.For example, emergency releases 890, 892 may be openings that provideaccess to manual release levers 894, 896 incorporated into lockingmechanism 871 for holding roller assembly 830 in obstacle or clearancemode. In some embodiments, a pin or similar tool is guided manually intothe openings of emergency releases 890, 892 to actuate manual releaselevers 894, 896. Other configurations for manually actuating emergencyreleases 890, 892 may include spring loaded buttons, spring pins,levers, or similar actuator members.

Referring to FIG. 14, a cross-section view of an example connecting link1200, such as may be used for first links 642, 644 or second links 646,648, and incorporating a shock absorber is shown. Connecting link 1200may include a first telescoping member portion 1210 and a secondtelescoping member portion 1212 held in movable relation to one anotherby a spring 1214. Note that other configurations of compactible butresistive link members are possible, including the use of pneumatic,fluid, or magnetic resistance between rigid members and/or the use ofone or more flexible members. The force necessary to compact spring 1214and shorten connecting link from its resting or maximum length to acompacted length may be configured by adjusting the spring constantand/or frictional forces resisting such displacement. In someembodiments, connecting link 1200 may include a displacement transducer1220 or other sensor for detecting the change in length of connectinglink 1200. Displacement transducer 1220 may generate a signal indicativeof the length change and communicate that signal to the robotic crawleror a control system for the robotic crawler. In some embodiments,displacement transducer 1220 will be mated with a wireless communicationsubsystem for providing sensor data. In some embodiments, displacementtransducer 1220 will have a wired connection to a data bus for sensorand other operational data within a robotic crawler. In someembodiments, displacement data from displacement transducer 1220 may beused to adjust the distance of the expanded state of the robotic crawlerto compensate for changes in gap width or particular obstacles.

Referring to FIGS. 14-17, an example configuration of visual sensormodules, including navigation modules, visual inspection modules, andcombinations thereof, is shown on a robotic crawler 1310 in a gap 1302between opposed machine surfaces 1304, 1306. Robotic crawler 1310 mayinclude a front traction module 1312, a middle traction module 1314, anda rear traction module 1316 that provide positioning and a sensorinterface for the visual sensor modules. In FIG. 13, a combination offour sensor modules 1320, 1322, 1324, 1326 is shown. Sensor module 1320may be a visual inspection module including a plurality of cameras andconnected to front traction module 1312. Sensor module 1320 may have afirst surface field of view 1330, a second surface field of view 1332,and a gap field of view 1334. Sensor modules 1322, 1324 may benavigation sensor modules including single cameras oriented in thedirection of travel, both being connected to middle traction module1314. Sensor module 1322 may have a gap field of view 1336 in one(axial) direction and sensor module 1324 may have a gap field of view1338 in an opposite (axial) direction. Sensor module 1326 may be anauxiliary sensor module with a single camera connected to rear tractionmodule 1316. An auxiliary sensor module may accommodate anotherfunction, such as tether attachment or another type of test sensor,while still incorporating at least one camera for collecting visualdata. Sensor module 1326 may have a gap field of view 1340 to the rearof the robotic crawler. In an alternate embodiment, sensor module 1326is another visual inspection module including a plurality of cameras,but only one camera is active for auxiliary navigation while sensormodule 1320 is being used for the primary inspection protocol.

Referring to FIG. 15, an example navigation sensor module 1400 is shown.In some embodiments, navigation sensor module 1400 may include a modulehousing 1410 defining a mounting interface 1412 and accommodatingfasteners 1414, 1416 for removably attaching navigation sensor module1400 to a robotic crawler. For example, mounting interface 1412 may beconfigured for removable attachment to a sensor interface on a roboticcrawler, such as a sensor interface on a module mounting frame or apreviously installed module, including a traction module with a sensorinterface. In some embodiments, module housing 1410 may includeelectronics, power source, communication channels, and/or optics for oneor more visual sensors or cameras. In some embodiments, mountinginterface 1412 may include a connector for power and/or communicationchannels for control and/or data signals to and from navigation sensormodule 1400. Navigation sensor module 1400 may include a visual sensorfor providing navigation data to a robotic crawler and/or controlsystem. In some embodiments, navigation sensor module 1400 includes acamera 1420 mounted to or embedded in module housing 1410. For example,camera 1420 may be a forward mounted video camera with a single apertureto gather visual data in the direction it is aligned with (such asforward or backward in a gap space). In some embodiments, camera 1420may incorporate a protective housing and/or include one or morecomponents mounted inside module housing 1410. In some embodiments,camera 1420 may be mounted on a movable mounting that enables the fieldof view direction of camera 1420 to be adjusted relative to the positionof navigation sensor module 1400 and the robotic crawler to which it isattached. For example, a movable mount may provide one or more pivotingadjustments that enable a user to change and set the direction of camera1420 prior to insertion in a gap. Another movable mount may includepowered adjustments that are configured for remote control through asensor control bus in the robotic crawler or wireless communication withthe robotic crawler and/or control system, enabling the field of view tobe changed during operation of the robotic crawler within the gap of themachine. Camera 1420 may include other adjustable parameters, such asfocus, aperture size, frame rates, and other settings for controllingvisual data quality (or quantity). In some embodiments, navigationsensor module 1400 may include on or more light sources to improvevisibility with camera 1420. In some embodiments, alternate navigationsensors may be used, including cameras with sensors for ultraviolet orinfrared spectrums or other location technologies (e.g. sonar, RFbeacons, magnetic imaging, etc.).

Referring to FIGS. 16-17, bottom and top views of an example visualinspection module 1500 are shown. In some embodiments, visual inspectionmodule 1500 may include a module housing 1510 defining a mountinginterface 1512 and accommodating fasteners 1514, 1516 for removablyattaching visual inspection module 1500 to a robotic crawler. Forexample, mounting interface 1512 may be configured for removableattachment to a sensor interface on a robotic crawler, such as a sensorinterface on a module mounting frame or a previously installed module,including a traction module with a sensor interface. In someembodiments, module housing 1510 may include electronics, power source,communication channels, and/or optics for one or more visual sensors orcameras. In some embodiments, mounting interface 1512 may include aconnector for power and/or communication channels for control and/ordata signals to and from visual inspection module 1500. Visualinspection module 1500 may include a plurality of visual sensors forproviding visual data to a robotic crawler and/or control system. Insome embodiments, visual inspection module 1500 includes cameras 1520,1522, 1524 mounted to or embedded in module housing 1510. For example,camera 1520 may be a video camera oriented toward a first surface withina machine gap to gather visual data from the first surface as therobotic crawler moves along that surface. Cameras 1522, 1524 may bevideo cameras oriented toward a second surface opposite the firstsurface within the machine gap to gather visual data from the secondsurface as the robotic crawler moves along that surface. In someembodiments, cameras 1520, 1522, 1524 may be recessed inside modulehousing 1510 to prevent clearance issues with an adjacent machinesurface. In some embodiments, cameras 1520, 1522, 1524 may include avariety of controls for position/direction of view, focus, field width,aperture size, frame rates, and other settings for controlling visualdata quality (or quantity). Some or all of these adjustments may bemanually set outside of the machine and/or are configured for remotecontrol through a sensor control bus in the robotic crawler or wirelesscommunication with the robotic crawler and/or control system, enablingdynamic adjustments during operation of the robotic crawler within thegap of the machine. In some embodiments, visual inspection module 1500may include light sources 1530, 1532, 1534, 1536, 1538 to improvevisibility with cameras 1520, 1522, 1524. For example, light sources1530, 1532, 1534, 1536, 1538 may be LED lights with diffusers recessedinto module housing 1510. In some embodiments, alternate inspectionsensors may be used, including cameras with sensors for ultraviolet orinfrared spectrums or other imaging technologies. In some embodiments,visual inspection module 1500 may include a sensor interface 1540opposite mounting interface 1512. For example sensor interface 1540 mayprovide a mounting surface and/or power or signal interfaces forreceiving the mounting interface of another sensor module to enablechaining of sensor modules. In some embodiments, sensor interface 1540includes a mounting surface 1542, fastener receptacle 1544, andconnectors 1546, 1548 for establishing a power, signal, and/orcommunication path between visual inspection module 1500 and a sensormodule attached to sensor interface 1540.

Referring to FIGS. 18-19, example sensor modules are shown for removableattachment to sensor interfaces on a robotic crawler. These sensormodules are shown as examples of different types of sensor or testmodules that may be created or adapted for use on a modular roboticcrawler.

Wedge tightness assessment module 1700 may be an example of a mechanicaltest module. Wedge tightness assessment module 1700 may include amechanical test assembly 1702 that may be deployed by the roboticcrawler at a desired crawler positioning based on control signals fromthe robotic crawler or control system. Mechanical test assembly 1702 mayprovide test data back to the robotic crawler or control system.Mechanical test assembly 1702 may be connected to a module housing 1710defining a mounting interface 1712 and accommodating fasteners 1714,1716 for removably attaching wedge tightness assessment module 1700 to arobotic crawler. For example, mounting interface 1712 may be configuredfor removable attachment to a sensor interface on a robotic crawler,such as a sensor interface on a module mounting frame or a previouslyinstalled module, including a traction module with a sensor interface.In some embodiments, module housing 1710 may include electronics, powersource, communication channels, and/or test components to support and/orinterface with mechanical test assembly 1702. In some embodiments,mounting interface 1712 may include a connector for power and/orcommunication channels for control and/or data signals to and from wedgetightness assessment module 1700. In some embodiments, wedge tightnessassessment module 1700 may include visual sensors, light sources, orother subsystems to assist in conducting the relevant test protocol. Inthe embodiments shown, wedge tightness assessment module 1700 may be aterminal sensor module because it does not include a sensor interfacefor receiving another sensor module.

Electromagnetic core imperfection detector module 1800 may be an exampleof an electrical test module. Electromagnetic core imperfection detectormodule 1800 may include an electrical test assembly 1802 that may beactivated by the robotic crawler at a desired crawler positioning basedon control signals from the robotic crawler or control system.Electrical test assembly 1802 may provide test data back to the roboticcrawler or control system. Electrical test assembly 1802 may beconnected to or embedded in a module housing 1810 defining a mountinginterface 1812 and accommodating fasteners 1814, 1816 for removablyattaching wedge tightness assessment module 1800 to a robotic crawler.For example, mounting interface 1812 may be configured for removableattachment to a sensor interface on a robotic crawler, such as a sensorinterface on a module mounting frame or a previously installed module,including a traction module with a sensor interface. In someembodiments, module housing 1810 may include electronics, power source,communication channels, and/or test components to support and/orinterface with electrical test assembly 1802. In some embodiments,mounting interface 1812 may include a connector for power and/orcommunication channels for control and/or data signals to and fromelectromagnetic core imperfection detector module 1800. In someembodiments, electromagnetic core imperfection detector module 1800 mayinclude visual sensors, light sources, or other subsystems to assist inconducting the relevant test protocol. In some embodiments,electromagnetic core imperfection detector module 1800 may include asensor interface 1840 opposite mounting interface 1812. For examplesensor interface 1840 may provide a mounting surface and/or power orsignal interfaces for receiving the mounting interface of another sensormodule to enable chaining of sensor modules. In some embodiments, sensorinterface 1840 includes a mounting surface 1842, fastener receptacle1844, and connectors 1846, 1848 for establishing a power, signal, and/orcommunication path between visual inspection module 1800 and a sensormodule attached to sensor interface 1840.

Referring to FIGS. 20-21, another configuration of a visual inspectionsensor is shown as end region inspection module 1900, according tovarious embodiments. End region inspection module 1900 may be configuredto extend into a region of a machine that a robotic crawler may nototherwise be able to reach and enable visual inspection of that region,such as an obstructed end region accessible through an inspection gapthat is too narrow for the robotic crawler and/or inaccessible to thetraction modules (or any other form of locomotion) of the roboticcrawler. End region inspection module 1900 may include a module housing1910 defining a mounting interface 1912 and accommodating fasteners1914, 1916 for removably attaching end region inspection module 1900 toa robotic crawler. For example, mounting interface 1912 may beconfigured for removable attachment to a sensor interface on a roboticcrawler, such as a sensor interface on a module mounting frame or apreviously installed module, including a traction module with a sensorinterface. In some embodiments, module housing 1910 may includeelectronics, power source, communication channels, and/or testcomponents to support and/or interface with other test components of endregion inspection module 1900. In some embodiments, mounting interface1912 may include a connectors 1918, 1920 for power and/or communicationchannels for control and/or data signals to and from end regioninspection module 1900. In some embodiments, end region inspectionmodule 1900 may include a fixed camera 1922 and light sources 1924,1926, 1928 mounted on or in module housing 1910. In some embodiments,end region inspection module 1900 includes an extension member 1930connected to module housing 1910. For example, extension member 1930 mayhave a fixed mount 1932 to module housing 1910 and comprise atelescoping member with a fixed portion 1934, a telescoping portion1936, and a slidably positionable joint 1938 between fixed portion 1934and telescoping portion 1936. In some embodiments, the telescopingmember may include an actuator in communication with the robotic crawleror the control system to adjust the length of the telescoping memberduring operation of the robotic crawler within the gap. In someembodiments, extension member 1930 further comprises one or moreslidable supports that assist with positioning extension member 1930.For example, extension member 1930 may include slidable magnetic pads1940, 1942, 1944, 1946 in laterally spaced pairs supported by brackets1948, 1950. Slidable magnetic pads 1940, 1942, 1944, 1946 may combine amagnetic core configured to provide an attachment force to one or moremagnetic surfaces of the machine with a non-stick pad surface configuredto move along the magnetic surface. Slidable magnetic pads 1940, 1942,1944, 1946 may be slidable on and detachable from the surface of themachine under the motive force of the robotic crawler, the telescopingmember, or another positioning element. Slidable magnetic pads 1940,1942, 1944, 1946 may be spaced laterally from extension member 1930 andtheir pad surfaces may define a plane for engaging with the surface ofthe machine. In one embodiment, one pair of slidable magnetic pads 1940,1942 may be attached to telescoping portion 1936 and the other pair ofslidable magnetic pads 1944, 1946 may be attached to fixed portion 1934.Note that while the example is shown with a configuration of four pads,other configurations with any number of pads may also be feasible.Extension member 1930 may connect to and support a rotatable cameraassembly 1950 at the distal end of extension member 1930. In someembodiments, rotating camera assembly 1960 may include a rotatinghousing 1962 with a camera 1964, such as a digital video camera, and alight source 1966, such as an LED with diffuser. In some embodiments,rotating camera assembly 1960 may further include an electronics module1968 and a motor module 1970. For example, electronics module 1968 mayinclude electronics for processing visual data collected by camera 1964and communicating that visual data to the robotic crawler or controlsystem, such as by wired or wireless video streaming, and motor module1970 may provide a motor, position index, and control interface forcontrollably moving rotating housing 1962, camera 1964, and light source1966 during an inspection protocol.

Referring to FIG. 22, a mechanical positioning module 2100 is shownaccording to various embodiments. Mechanical positioning module 2100 maybe used to position a sensor module within the gap and relative to acrawler position of a robotic crawler. For example, mechanicalpositioning module may include one or more positionable joints to move asensor interface (and an attached sensor module) to a desired heightbetween the machine surfaces that define the gap. Mechanical positioningmodule 2100 is shown in a gap 2102 between a first surface 2104 and asecond surface 2106 and attached to a robotic crawler 2110 positioning asensor interface housing 2140 to clear a lip 2108. In some embodiments,mechanical positioning module 2100 includes a mounting interface housing2120 that connects to a sensor interface of robotic crawler 2110, amechanical positioning assembly 2130 connected to mounting interfacehousing 2120 at one end, and sensor interface housing 2140 connected tothe other end of mechanical positioning assembly 2130. For example,mounting interface housing 2120 may include a mounting interface similarto those described above for sensor modules and compatible with one ormore sensor interfaces on robotic crawler 2110. Mounting interfacehousing 2120 may include a motor and other components for receivingcontrol signals and controlling the position of mechanical positioningassembly 2130. Mechanical positioning assembly 2130 may include avariety of positionable joints, members, and actuators for performingthe desired positioning operations, such as a parallel lift capable ofraising and lowering sensor interface housing 2140 while maintaining iton plane parallel to the base of robotic crawler 2110. Sensor interfacehousing 2140 may provide a sensor interface similar to those describedabove for receiving, positioning, and connecting a sensor module. Insome embodiments, sensor interface housing 2140 may be replaced with asensor housing for an integrated sensor module with a positioningassembly.

Referring to FIG. 23, a stacked configuration 2300 of sensor modules2310, 2320, 2330 is shown according to various embodiments. For example,sensor module 2310 may be an electrical test module similar toelectromagnetic core imperfection detector module 1800 in FIG. 19.Sensor module 2320 may be a visual inspection module similar to visualinspection module 1500 in FIG. 17. Sensor module 2330 may be amechanical test module similar to wedge tightness assessment module 1700in FIG. 18. Sensor modules 2310, 2320, 2330 may be connected to acrawler sensor interface 2302 supported by a traction module 2304,providing electrical, mechanical, and communication connections to therobotic crawler. Sensor modules 2310, 2320, 2330 may each be activatedand controlled by the robotic crawler independently at desired crawlerpositions based on control signals from the robotic crawler or controlsystem. Any number of sensor modules 2310, 2320, 2330 may be stacked andcontrolled in this fashion to the limits of the mechanical strength ofmodules and interfaces, as well as robotic crawler balance and thelimits of whatever power and communication paths the interfacearchitecture supports. Sensor modules 2310, 2320, 2330 may each providedata back to the robotic crawler or control system independently. Eachof sensor modules 2310, 2320, 2330 may be connected to or embedded inmodule housings 2312, 2322, 2332 defining mounting interfaces 2314,2324, 2334 for removably attaching to the preceding sensor module orcrawler sensor interface 2302. In some embodiments, mounting interfaces2314, 2324, 2334 may provide robust mechanical interfaces to adjacentsensor interfaces, such that 2-5 sensor modules may be stacked. In someembodiments, module housings 2312, 2322, 2332 may include electronics,power sources or channels, communication channels, and/or testcomponents to support and/or interface with their respective sensors. Insome embodiments, mounting interfaces 2314, 2324, 2334 may includeconnectors for power and/or communication channels for control and/ordata signals to and from sensor modules 2310, 2320, 2330. Sensor modules2310, 2320 may include sensor interfaces 2316, 2326 opposite mountinginterfaces 2314, 2324. For example, each mated pair of crawler sensorinterface 2302 and sensor interfaces 2316, 2326 with mounting interfaces2314, 2324, 2334 may include built in pins on one side and matingreceptacles on the other side to establish operative electrical and/orsignal contact between adjacent sensor modules 2310, 2320, 2330.Interconnected sensor modules 2310, 2320, 2330 may provide one or morecontinuous channels through their respective module housings 2312, 2322,2332 to enable power and signals to pass through. In some embodiments,these continuous channels may include parallel channels enablingseparate pathways to each of sensor modules 2310, 2320, 2330 and in someembodiments serial and/or multiplexed channels may be used. Sensormodule 2330 may be a terminal sensor module that does not include asensor interface and may only be used at the distal end of stackedconfiguration 2300. In stacked configuration 2300, sensor module 2310may be connected to crawler sensor interface 2302 by mounting interface2314 and to sensor module 2320 by sensor interface 2316. Sensor module2320 may be connected to sensor module 2310 by mounting interface 2324and to sensor module 2330 by sensor interface 2326. Sensor module 2330may be connected to sensor module 2320 by mounting interface 2334 andmay terminate the stack or chain of sensor modules 2310, 2320, 2330extending from crawler sensor interface 2302. In some embodiments,sensor modules 2310, 2320, 2330 may be operated simultaneously toperform simultaneous inspections or tests independently or based onrelationships between sensor modules 2310, 2320, 2330, the roboticcrawler, and or other sensor modules mounted elsewhere on the roboticcrawler.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a”, “an” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises”and/or “comprising,” when used in this specification, specify thepresence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

The corresponding structures, materials, acts, and equivalents of allmeans or step plus function elements in the claims below are intended toinclude any structure, material, or act for performing the function incombination with other claimed elements as specifically claimed. Thedescription of the present disclosure has been presented for purposes ofillustration and description, but is not intended to be exhaustive orlimited to the disclosure in the form disclosed. Many modifications andvariations will be apparent to those of ordinary skill in the artwithout departing from the scope and spirit of the disclosure. Theembodiment was chosen and described in order to best explain theprinciples of the disclosure and the practical application, and toenable others of ordinary skill in the art to understand the disclosurefor various embodiments with various modifications as are suited to theparticular use contemplated.

What is claimed is:
 1. A system comprising: a robotic crawler having aplurality of multidirectional traction modules, an expandable bodyconnected to the multidirectional traction modules, and a plurality ofsensor modules, each of the plurality of sensor modules including amounting interface, each mounting interface configured to attach to asensor interface on the robotic crawler or one of the plurality ofsensor modules, wherein the plurality of sensor modules are positionedrelative to the plurality of multidirectional traction modules; and acontrol system in communication with the robotic crawler, the controlsystem providing a control signal to the robotic crawler to navigate aninspection path within an annular gap of a machine, wherein navigatingthe inspection path includes axial movement and circumferential movementof the plurality of multidirectional traction modules to inspect themachine using the plurality of sensor modules.
 2. The system of claim 1,wherein the robotic crawler has a collapsed state and an expanded state,the collapsed state providing the robotic crawler with a first thicknessless than an entrance gap width for the annular gap of the machine andthe expanded state providing the robotic crawler with a second thicknessgreater than the entrance gap width and not greater than a working gapwidth for the annular gap of the machine, the machine selected from agenerator, an electric motor, or a turbomachine.
 3. The system of claim2, wherein the robotic crawler includes at least one manual emergencyrelease that transforms the robotic crawler from the expanded state tothe collapsed state without a control signal from the control system. 4.The system of claim 1, wherein the plurality of multidirectionaltraction modules include a traction roller disposed within a rotatableframe, wherein the rotatable frame is controllably moved between a firstposition for axial movement and a second position for circumferentialmovement.
 5. The system of claim 4, wherein the rotatable frame iscontrollably moved around a 360 degree arc for travel between the firstposition for axial movement and the second position for circumferentialmovement.
 6. The system of claim 1, wherein the robotic crawler includesa communication channel in communication with the control system and aplurality of sensor interfaces disposed in physically separated portionsof the robotic crawler, the plurality of sensor interfaces connected tothe communication channel and each of the plurality of sensor interfacesproviding a sensor data channel for at least one of the plurality ofsensor modules.
 7. The system of claim 1, wherein the plurality ofsensor modules include a plurality of sensor types selected fromnavigation sensors, visual inspection sensors, structural test sensors,or electrical test sensors.
 8. The system of claim 7, wherein theplurality of sensor modules include a first sensor module having a firstsensor type and a second sensor module having a second sensor typedifferent from the first sensor type.
 9. The system of claim 1, whereinthe control system provides fully automated inspection of all machinesurfaces within the annular gap using the robotic crawler to follow aselected inspection path.
 10. The system of claim 1, wherein the controlsystem comprises a user interface displaying sensor data from theplurality of sensor modules and enables manual override of automatedinspection navigation of the robotic crawler.
 11. The system of claim 1,wherein the robotic crawler is one of a plurality of robotic crawlersoperating within the annular gap of the machine and the control systemis configured to communicate with the plurality of robotic crawlers andguide the plurality of robotic crawlers on a plurality of inspectionpaths.
 12. The system of claim 1, further comprising a tether reel thatmanages a cable connected to the robotic crawler, wherein the tetherreel includes a tension management function that automatically adjusts acable tension during operation of the robotic crawler.
 13. A methodcomprising: inserting a robotic crawler into an annular gap of amachine; expanding an expandable body of the robotic crawler such that aplurality of multidirectional traction modules on the robotic crawlerengage opposed surfaces in the annular gap; traversing an inspectionpath within the annular gap using axial movements and circumferentialmovements of the robotic crawler; and performing a plurality ofinspection tests along the inspection path using a plurality of sensormodules, each of the plurality of sensor modules including a mountinginterface, each mounting interface attached to a sensor interface on therobotic crawler or one of the plurality of sensor modules, wherein theplurality of sensor modules is attached to the robotic crawler.
 14. Themethod of claim 13, further comprising providing at least one controlsignal to the robotic crawler from a control system to control at leastone of the expanding, traversing, and performing.
 15. The method ofclaim 14, wherein the control system provides fully automated inspectionof all machine surfaces within the annular gap using the robotic crawlerto follow a selected inspection path, the machine selected from agenerator, an electric motor, or a turbomachine.
 16. The method of claim14, further comprising displaying sensor data from the plurality ofsensor modules through a user interface of the control system andmanually overriding an automated navigation of the robotic crawler alongthe inspection path.
 17. The method of claim 14, wherein the roboticcrawler is one of a plurality of robotic crawlers operating within theannular gap of the machine and the at least one control signal includesa plurality of control signals to the plurality of robotic crawlers tosimultaneously traverse a plurality of inspection paths within theannular gap.
 18. The method of claim 13, further comprising: collapsingthe expandable body of the robotic crawler such that the plurality ofmultidirectional traction modules on the robotic crawler disengage atleast one surface in the annular gap; and removing the robotic crawlerfrom the annular gap of the machine through an entrance gap, wherein theentrance gap has an entrance gap width that is less than an annular gapwidth of the annular gap.
 19. The method of claim 18, wherein collapsingthe expandable body of the robotic crawler includes actuating a manualemergency release without receiving a control signal from a controlsystem to control the collapsing.
 20. The method of claim 13, whereintraversing the inspection path includes controllably rotating tractionrollers in the plurality of multidirectional traction modules between afirst position for axial movement and a second position forcircumferential movement.
 21. The method of claim 20, wherein traversingthe inspection path includes controllably rotating traction rollers inthe plurality of multidirectional traction modules around a 360 degreearc for travel between the first position for axial movement and thesecond position for circumferential movement.
 22. The method of claim13, wherein the robotic crawler includes a plurality of sensorinterfaces disposed in physically separated portions of the roboticcrawler, the plurality of sensor interfaces connected to a communicationchannel and each of the plurality of sensor interfaces providing asensor data channel for at least one of the plurality of sensor modules,the method further comprising removing a first sensor module from aselected sensor interface and connecting a second sensor module to theselected sensor interface.
 23. The method of claim 13, wherein theplurality of sensor modules include a plurality of sensor types selectedfrom navigation sensors, visual inspection sensors, structural testsensors, or electrical test sensors, wherein performing the plurality ofinspection tests uses the plurality of sensor types.
 24. The method ofclaim 13, further comprising automatically adjusting a cable tension ofa cable connected to the robotic crawler during operation of the roboticcrawler using a tether reel.
 25. A robot control system comprising: acrawler configuration module providing operating instructions for arobotic crawler having a plurality of multidirectional traction modules,an expandable body connected to the multidirectional traction modules,and a plurality of sensor modules, each of the plurality of sensormodules including a mounting interface, each mounting interfaceconfigured to attach to the expandable body or one of the plurality ofsensor modules; at least one inspection path definition correlating toan inspection path within an annular gap of a machine, the machineselected from a generator, an electric motor, or a turbomachine, and anautonomous navigation module in communication with the robotic crawlerto provide a control signal for the robotic crawler to traverse theinspection path using axial movements and circumferential movements ofthe plurality of multidirectional traction modules to inspect themachine using the plurality of sensor modules.